PapiDefense is a very nice arcade game for the Mac. In this game, you have to defend Mr. Papi from a rocket attack by shooting down those rockets with some Papi rockets of your own. Mr. Papi is located on the left side of the screen, protected by three barriers. Under Mr. Papi is your rocket launching platform. You shoot the rockets by pressing your left mouse button. The longer you hold the button, the higher the rocket will go. If you barely press the button, the rocket will fly a little bit up and forward and then fall close to the platform. The aiming mechanics take a little while to get used to, but they are not hard.
Rockets start coming your way when the level begins, and they will be faster and faster as the game progresses. After a minute or so, the screen will be filled with rockets. The good thing is that every one of your shots can take down multiple rockets if you aim them well.
The game has music, which is very constant and not annoying if you play the game for a short while.
In short, this is a nice casual game that isn't very challenging, but it can be fun.